In a conventionally used optical print head, as shown in FIG. 17, there are provided a plurality of light-emitting devices and a plurality of driving ICs. The light-emitting devices are each composed of a plurality of light-emitting sections (it is to be understood that what is called a “light-emitting section” in the present specification corresponds to what is called a “light-emitting element” in the appended claims). The driving ICs each include, as shown in FIG. 18, a shift register 101 that takes in data signals, a latch circuit 102 that parallelly takes in the data signals taken in by the shifter register 101, a drive circuit 103 that drives the light emitting device, a current supply circuit 104 that supplies electric current to the drive circuit 103, and a timing control circuit 105 that supplies predetermined timing signals to various portions of the driving IC. Now, the conventional optical print head will be described assuming that, as shown in FIG. 17, it includes 26 driving ICs “b1” to “b26” that are connected in series and 4,992 light-emitting sections #1 to #4992 that are driven by those 26 driving ICs “b1” to “b26.”
In the optical print head configured as described above, first, the driving IC “b” takes in four-bit data signals fed thereto via data input terminals SI0 to SI3 and moves them to the shift register 101 in synchronism with a clock pulse CLK. The shift register 101 then outputs the thus received four-bit data signals via data output terminals SO0 to SO3 to the data input terminals SI0 to SI3 of the next driving IC in synchronism with a clock pulse CLK.
Simultaneously, the clock pulse fed in via a clock input terminal CI is fed out through a buffer via a clock output terminal CO so as to be fed to the clock input terminal CI of the next driving IC. Thus, as shown in FIG. 19, when the 1,248th clock pulse CLK is fed in, the shift registers 101 of the 26 driving ICs “b1” to “b26” take in 4,992 data signals, each taking in 4×48 (192) data signals.
When 4,992 data signals have been taken in in this way, next, a load signal LOAD is fed to a load signal input terminal LI of the driving IC. When a timing signal produced from this load signal LOAD is fed to the latch circuit 102, which is of the 192-bit type, the 192 data signals taken in by the shift register 101 are stored therein.
Simultaneously, the load signal LOAD fed in via the load signal input terminal LI is fed out through a buffer via a load signal output terminal LO so as to be fed to the load signal input terminal LI of the next driving IC. Thus, when, as shown in FIG. 19, the load signal LOAD is fed in, the data signals taken in by the shift registers 101 of the 26 driving ICs “b1” to “b26” are stored in the respective latch circuits 102.
On the basis of 4,992 data signals stored in this way in the latch circuits 102 of the driving ICs “b1” to “b26,” with 192 data signals stored in the latch circuit 102 of each driving IC, the drive circuit 103 supplies electric current to terminals DO1 to DO192 during the period in which a strobe signal STB is low and thereby drives the light-emitting sections #1 to #4992 to achieve printing of one line. While the drive circuit 103 is operating in this way, the load signal LOAD is turned low, and a clock pulse CLK is fed in again to take in the data signals of the next line.
The optical print head also has, as shown in a top view thereof in FIG. 1, an SLA (self-focusing lens array) 2 for covering the light-emitting device array 1 composed of a plurality of light-emitting sections and arranged in the middle, a lens holder 3 for keeping the SLA 2 in a fixed position, and positioning pins 4a and 4b for positioning the plurality of light-emitting sections constituting the light-emitting devices arranged in the light-emitting device array 1. The light-emitting sections constituting the light-emitting device array 1 are so positioned as to be located on the straight line connecting between the positioning pins 4a and 4b. 
Conventionally, an optical print head like that described above is incorporated in a printer or the like to achieve printing on paper. Here, a bend in the LED array in which light-emitting devices mounted on a circuit board are arranged, or a bend in the optical axes of the lenses provided in the optical print head, or a bend in those lenses themselves results in a bend in the imaging positions. Suppose now that light-emitting devices are arranged in a direction called the X direction and the direction perpendicular thereto is called the Y direction. Then, a bend as described above occurs in the Y direction. Hereinafter, such a bend in the Y direction is called as a “Y bend.”
A Y bend is observed, for example, as deviations of the imaging positions of light-emitting sections in the Y direction as shown in graphs in FIGS. 20 and 21. Such deviations of the imaging positions occur also as a result of the line connecting between the positioning pins 4a and 4b deviating obliquely in the Y direction.
A Y bend greatly degrades print quality in a tandem-type printer or the like that is provided with a plurality of optical print heads to achieve color printing. Moreover, to alleviate such lowering of print quality, it is necessary to sort out acceptable optical print heads from unusable ones, adjust lenses or sort out acceptable ones from unusable ones, or otherwise perform extra operation. This increases the costs of optical print heads and printers provided with such optical print heads.
An object of the present invention is to provide a driving IC that corrects deviations in imaging positions resulting from a mechanical or optical bend in an optical print head, and to provide an optical print head provided with such a driving IC.